Electric current sensor utilizing a compensating trace configuration

• US 5,874,848 A
• Filed: 07/09/1997
• Issued: 02/23/1999
• Est. Priority Date: 07/09/1997
• Status: Expired due to Term

• Current Assignee: OECO, LLC (Meggitt PLC)
• Original Assignee: Beloit Technologies, Inc.
• Inventors: Grama, George V., Drafts, William A.
• Primary Examiner(s): Callahan, Timothy P.
• Assistant Examiner(s): Luu, An T.
• Application Number:
  US08/891,878
• Time in Patent Office: 594 Days
• Field of Search: 327/511, 324/117 H, 324/225, 324/251
• US Class Current: 327/511
• CPC Class Codes: G01R 15/202 using Hall-effect devices Hall elements in arrangements for measuring electrical power G01R21/08
• CPC Class Codes: G01R 33/07 Hall effect devices

Abstract

An electric current sensor employing a Hall effect generator and a ferrite substrate to be used in the measuring of electrical currents flowing in a current carrying conductor comprising a toroid core having a first and a second gap, a Hall effect generator, a current source, an amplifier, and a trace configuration positioned on the substrate for electrically coupling the amplifier to the Hall effect generator. The toroid core and ferrite substrate forming the complete magnetic circuit for the flow of the magnetic field. The trace configuration thereby being routed so as to be exposed to the magnetic field in two different impinging directions so to compensate for any unwanted induced voltages from being introduced into the output voltage thereby achieving an improved transient response.

Claims

1. A current sensor for sensing electrical current in a current carrying conductor, said current sensor comprising in combination:

a substrate having a planar surface;

a toroid core coupled relative to said substrate, said toroid core forming a first and a second gap relative to said substrate and facilitating the flow of a magnetic field;

a Hall effect generator coupled to said planar surface, said Hall effect generator being free of inductive leads and positioned within said first gap;

current source means for providing a control current to said Hall effect generator, said current source means being electrically coupled to said Hall effect generator;

amplifier means for amplifying the output voltage from said Hall effect generator; and

a trace configuration, said trace configuration being electrically coupled to said amplifier means and to said Hall effect generator, said trace configuration being positioned on said substrate so as to be exposed to the magnetic field in two different impinging directions;

whereby the magnetic field created in said toroid core flows across said gap and across said Hall effect generator when electrical current flows through the current carrying conductor, said Hall effect generator producing an output voltage that is proportional to the magnetic field, said trace configuration providing for compensation of any unwanted induced voltages from being introduced into the output voltage thereby achieving an improved transient response.

2. The current sensor as recited in claim 1, wherein said substrate is comprised of a ferrite material thereby facilitating magnetic flow therethrough.

3. The current sensor as recited in claim 2, wherein said toroid core is a half toroid, said half toroid being coupled relative to said planar surface, whereby said substrate formed of ferrite material completes the magnetic flow path.

4. The current sensor as recited in claim 3, wherein said current sensor further comprises a second Hall effect generator coupled to said planar surface of said substrate and positioned within said second gap, said second Hall effect generator being electrically coupled to said amplifier means by way of said trace configuration.

5. The current sensor as recited in claim 1, wherein said trace configuration includes output leads positioned so as to pass within said first and second gaps thereby being exposed to the magnetic field in two different impinging directions and facilitating the compensation of any unwanted induced voltages in the output leads.

6. The current sensor as recited in claim 4, wherein said Hall effect generator and said second Hall effect generator are directly deposited onto said substrate.

7. The current sensor as recited in claim 4, wherein said Hall effect generator and said second Hall effect generator are in the form of flip-chip packaged devices coupled to said substrate.

8. A method for sensing current in a current carrying conductor comprising the steps of:

providing a substrate, and a toroid having a first and second gap, the toroid being coupled to the substrate;

placing the current carrying conductor in cooperative position relative to the toroid facilitating magnetic coupling;

creating a magnetic field within the toroid in proportion to the current flowing in the current carrying conductor;

providing a Hall effect generator positioned within the first gap so to be exposed to the magnetic field;

producing a Hall effect voltage proportional to the magnetic field;

electrically coupling the Hall effect voltage to an amplifier means by way of a trace configuration, the trace configuration being routed so to be exposed to the magnetic field in two different impinging directions; and

detecting the amplified Hall effect voltage and correlating the value with a representative current amount.

9. The method as recited in claim 8, wherein the step of providing a substrate is comprised of providing a substrate formed of ferrite material and the toroid is in the shape of one half a toroid whereby the substrate of ferrite material completes the magnetic flow path.

10. The method as recited in claim 9, wherein the step of providing a Hall effect generator is further comprised of providing a second Hall effect generator positioned within the second gap.